Hydraulic pressure feedback control valve

ABSTRACT

Disclosed herein is a hydraulic valve with a valve plunger, a metering valve and feedback piston in tandem. A metering valve member has one end fixed to the end of the plunger and a free end supported in a sleeve to guide a valve portion having a variable cross section through a metering orifice to exhaust fluid into a vent passage and vary the pressure at the valve outlet as the valve plunger is moved. Interchangeable metering valve assemblies containing valve members and orifices with different configurations and dimensions afford different metering characteristics, and thus, different output pressure ranges for different valve applications. The feedback piston is freely reciprocal axially of the plunger and has a feedback face exposed to the valve output chamber and another piston face engaging the free end of the metering valve member to provide a counterforce on the plunger and a &#39;&#39;&#39;&#39;feel&#39;&#39;&#39;&#39; of the output pressure to the valve operator.

0 United States Patent [151 afisnms Byers 51 Jan. 25, W72

[ HYDRAULIC PRESSURE FEEDBA'CK Primary Examiner-M. Cary Nelson (:QN'MRULVALVE I Assistant Examiner-Robert J. Miller Attorney-Wheeler, Wheeler,House 8: Clemency [72] inventor: James R. lByers, 3620 Mountain Drive,

Brookfield, Wis. 53005 [57] ABSTRACT Filed! 4, 1 70 Disclosed herein isa hydraulic valve with a valve plunger, a [2]] Appl Noi 66,313 meteringvalve and feedback piston in tandem. A metering valve member has one endfixed to the end of the plunger and a free end supported in a sleeve toguide a valve portion hav- [52] U.S. C1 ..l37/625.26, l37/625.49,251/122 ing a variable cross section through a metering orifice to ex-[51] lint. Cl... ..F16k 11/07 haust fluid into a vent passage and varythe pressure at the [58] Field oli Search ..137/625.26,625.2,504, 596.1,valve outlet as the valve plunger is moved. Interchangeable 137/596.2;188/352 metering valve assemblies containing valve members and orificeswith different configurations and dimensions afford dif- [56] ReferencesCited ferent metering characteristics, and thus, different outputpressure ranges for different valve applications. The feedback UNITEDSTATES PATENTS piston is freely reciprocal axially of the plunger andhas a feed- 738,026 9 1903 Gill ..l37/625.26 back to the valve Chamberand Omar 1,063,975 6/1913 King and Weston 137/625 26 X piston faceengaging the free end of the metering valve 2,837,148 6/1958 Jay 137/62526 member to provide a counterforce on the plunger and a feel" 3,156,2581 H1964 Moody n 137/504 of the output pressure to the valve operator.3,421,542 1/1969 Adams et a1 ..l37/504 9 Claims, 5 Drawing FiguresHYDRAULIC PRESSURE FEEDBACK (ION'IIIOIL VAIJl/IE BACKGROUND OF INVENTIONThe invention relates to hydraulic valves and more particularly tovalves providing a variable output pressure.

SUMMARY OF INVENTION The invention provides a hydraulic valve in whichflow from the valve inlet to the valve outlet is controlled by axialmovement of a plunger or valve spool. The pressure at the valve outletis controlled by a metering valve in tandem with the plunger. Themetering valve controls flow through a branch passage which communicateswith a vent passage and includes an orifice and a valve member in theform of a rod with one end of the rod connected to and extending axiallyof the valve plunger. The free end of the rod is supported and guidedfor movement in the orifice by an aperture in a guide sleeve. Themetering valve member has a variable cross section for a portion of itslength which can be in the form of an axially tapered flat or land,located intermediate the ends of the rod. As the valve plunger is movedaxially under pressure of the control apparatus, the metering valvemoves with the plunger and the land progressively fills the orifice todecrease fluid flow to a vent passage, and thus increase the pressure atthe valve outlet.

Insertable pressure cartridges or metering valve assemblies containingmetering valve rods of different cross sections and orifices ofdifferent diameters readily adapt the valve for various controlapplications with different pressure requirements.

To provide a feel to the valve plunger so that the valve operator cansense the increase and decrease in output pressure upon axial movementof the plunger, the valve includes a feedback piston assembly whichprovides a hydraulic feedback pressure or counterforce on the valveplunger which is proportional to pressure output. In this regard, afreely reciprocal piston guided in a sleeve adjacent the output chamberhas one end exposed to the output chamber and another end which bearsagainst the free end of the metering valve member. As pressure increasesin the output chamber as the metering orifice is filled by the valvemember, a corresponding increase in pressure on the exposed piston faceaffords sensing of the changing output pressure by the valve operator.

The feedback pressure is entirely dependent on the area of the pistonface and on the hydraulic pressure in the output chamber which isdependent on the position of the valve spool and the metering valvemember.

The invention also provides interchangeable feedback cartridges orfeedback piston assemblies which are easily inserted in the valve toprovide varying feedback forces or pressures on the valve plunger. Thefeedback piston assemblies contain pistons and guide sleeves of variousdiameters with piston faces of different areas.

It is an object of the invention to provide a hydraulic valve withvariable pressure output in which the pressure variations are controlledby a metering valve having a metering valve member with one endconnected to the valve plunger and a free end supported remote from theplunger by a guide sleeve and in which a variable cross section on themetering rod cooperates with an orifice to exhaust fluid to a ventpassage.

It is a further object of the invention to provide a hydraulic valvewhich utilizes a free piston having an exposed face in an output chamberto provide a counterforce on the valve plunger which is transmitted tothe plunger by the metering valve member and which force is proportionalto the pressure in the output chamber.

Further objects and advantages of the present invention will becomeapparent from the following disclosure.

DESCRIPTION OF DRAWINGS FIG. 1 is a vertical sectional view of ahydraulic valve in accordance with the invention.

FIG. 2 is a sectional view taken along Line 22 of FIG. 11.

FIG. 3 is a sectional view taken along Line 33 of FIG. ll.

FIG. 4b is a perspective view of a modified feedback piston assembly forthe hydraulic valve shown in FIG. ll.

FIG. 5 is a perspective view of a further embodiment of the meteringvalve member.

DESCRIPTION OF THE PREFERRED EMBODIMENT Although the disclosure hereofis detailed and exact to enable those skilled in the art to practice theinvention, the physical embodiments herein disclosed merely exemplifythe invention which may be embodied in other specific structures.

In the drawings, FIG. I discloses a hydraulic valve which is generallydesignated lift and which includes a valve body 12 with an axial bore Mwhich receives a valve plunger or spool 116. The plunger 16 is providedwith an eye 18 and a land 20, and can be connected to any form of inputcontrol member or control apparatus. The valve It] includes an inletport 22, and outlet port 24 and a first passage 26 which provides fluidcommunication between the inlet and outlet ports.

In accordance with the invention, means are provided for varying thehydraulic pressure at the outlet 24 in response to axial movement ofsaid plunger 116. In the disclosed construction, the means includes ametering valve member 32 in the form of a cylindrical rod. Means areprovided to connect the valve member 32 to the plunger to. As disclosed,the valve member 32 has an end 33 which is received and anchored in anaxis aperture 34 in the plunger. Means are also provided for supportingand guiding the free end 35 of the metering valve member 32. Asdisclosed, the means comprises a guide sleeve 36 which has an aperture38 coaxial with the plunger 16.

The valve member 32 has a tapered or frustoconical portion 39 locatedintermediate the ends 33, 35. Axial movement of the plunger 16 causesmovement of the frustoconical portion 33 through an orifice All in aplate d2 located against a shoulder 41 and secured by a spacer 43. Asecond passage or branch passage d4 provides communication between thefirst passage 26 and the orifice All). Fluid escaping through theorifice 40 into metering chamber I6 is exhausted to the reservoirthrough a vent passage 48.

FIG. 5 discloses a modified embodiment of a metering valve member 50. Inthis embodiment, the valve member 50 has an axially tapered flat orshear land 52 intermediate the ends 54, 56 of a cylindrical rod. Thedegree of taper and depth of grinding on the properly selected diameterof round can afford van ous metering valve characteristics for differingvalve output pressure requirements.

Metering valve cartridges 58 comprising the valve member 50 and a disc60 with different tapers or cross sections and orifice diameters areeasily inserted in the bore M to provide the desired output pressurecharacteristics.

The invention also provides means for biasing the plunger I6 inopposition to the input force on the plunger with the biasing pressuredependent on the valve output pressure. In the disclosed construction,the means comprises a free piston which is freely reciprocal in anaperture 72 in a guide sleeve 7% and interfits to provide a fluid seal.The guide sleeve M is located in an output chamber 75 and coaxial of theplunger 16 and the valve member 32. The piston 70 has a face 76 whichengages and bears against the end 35 of the valve member 32.

The other end or face 73 of the piston 70 is exposed to the hydraulicfluid and pressure in the output chamber 75. The counterforce orfeedback force is in opposition to the input force on eye I8 and in thedirection designated by the arrow ill]. The magnitude of the feedbackforce is a function of the area of face 78 and the pressure in theoutput chamber. Thus, as the pressure in the output chamber 75 increasesas the tapered portion 33 of the valve member 32 fills the orifice ll)and decreases the fluid flow to the vent passage 4% and the pressure inthe output chamber 75 increases, the feedback force also increases toprovide a feel" of the increased pressure to the valve operator.

The guide sleeve 74 is secured against a spacer ill by a spring 32located between the spacer 3t and a threaded adapter 84 which has acounterbore 86 with a shoulder 88 which serves as a stop for piston 70.

Leakage around the end 35 of valve member 32 and between the piston 70and the guide sleeve 74 escapes into passage 48 through an aperture 90in spacer 81.

In operation of the valve, fluid output commences as the plunger 16 ismoved from the FIG. 1 position to register the land 20 with the inletport 22. Initially, the output pressure and thus the feedback pressurewill be at a minimum because of maximum flow through the meteringorifice 40. The metering valve characteristics can be predetermined toprovide a linear or nonlinear output pressure variation with axialmovement of the plunger. The feedback pressure can also be predeterminedto afford a linear or nonlinear increase in feedback force, In addition,the axial position of the plunger can be calibrated to afford a visualindication of pressure output.

The valve of the invention may be constructed in the variousconfigurations known to the art including: closed center, open center,pressure-compensated, parallel, series-stackable, nonstackable, with orwithout high-pressure carry over, manual-operated, cam-operated,pilot-operated, solenoidcontrolled, servo-controlled,micrometer-controlled, rotary servo-controlled air-controlled,radio-controlled, and single or multiple detented.

What is claimed is:

l. A hydraulic valve comprising a valve body having an axial bore,plunger reciprocally received in said bore, said body having an inletport and an outlet port, a first passage connecting said inlet port tosaid outlet port, means defining a metering chamber in said body, a ventpassage communicating with said metering chamber, means defining ametering orifice in said metering chamber, a second passage affordingcommunication between said first passage and said metering chamber, ametering valve member having a portion with a variable cross sectionmovable in said orifice, means for supporting and guiding one end ofsaid metering valve member and means connecting said metering valvemember of said plunger to afford movement of said valve member in saidorifice in response to movement of said plunger to vary output pressureat said outlet port.

2. A hydraulic valve in accordance with claim 1 wherein said means forsupporting and guiding one end of said metering valve member comprises aguide sleeve having an axial aperture which freely receives said one endof said metering valve member and interfits with said one end to providea fluid seal between said valve member and said sleeve.

3. A hydraulic valve in accordance with claim 1 wherein said meteringvalve member is cylindrical and said variable cross section of saidmetering valve member is in the form of axially tapered flat.

4. A hydraulic valve in accordance with claim 1 wherein said meteringvalve member has a frustoconical portion intermediate two cylindricalportions.

5. A hydraulic valve in accordance with claim 1 including a free piston,means for supporting said free piston in said valve body for axialmovement, said free piston having one end exposed to said first passageadjacent said outlet port and another end engaging said metering valvemember to transmit a counter force from said piston to said plunger in adirection opposite to the input force on said plunger.

6. A hydraulic valve in accordance with claim 5 wherein said means forsupporting said free piston comprises a guide sleeve having an axialaperture with said piston freely slidable therein and interfitting insaid aperture to provide a fluid seal, a spacer in said valve body and aspring biasing said sleeve against said spacer.

7. A hydraulic valve in accordance with claim 6 wherein said valve bodyhas an output chamber communicating with said first passage, an adapterthreadably received in said valve body and having an aperture definingsaid valve outlet, said outlet communicating with said output chamber, acounterbore in said adapter providing a stop for said piston and whereinsaid spring is arranged around the path of travel of said piston topermit movement of said piston within the interior of said spring.

8. A hydraulic valve comprising a valve body having a bore, a valveinlet and a valve outlet, a first passage connecting said inlet andoutlet, a plunger reciprocally received in said bore for controllingflow through said first passage from said inlet to said outlet, ametering chamber, a second passage communicating with said first passageand said metering chamber, a metering valve assembly including meansdefining an orifice and a metering valve member located axially of saidplunger and movable with said plunger, said valve member having aportion with a variable cross section receivable in said orifice, a ventpassage communicating with said metering chamber, a free piston locatedin tandem with said metering valve member and having one end engagingsaid metering valve member and another end exposed to said first passagedownstream from said second passage so that fluid pressure on saidexposed end causes a counterforce on said piston which is transmitted tosaid plunger by said metering valve member and which opposes the inputforce on the plunger.

9. A hydraulic valve comprising a valve body having an axial bore, aplunger reciprocally received in said bore, said valve body having aninlet port and an outlet port, a first passage connecting said inletport and said outlet port, a metering chamber in said body, a ventpassage communicating with said metering chamber and adapted tocommunicated with a reservoir, an orifice for permitting fluid flow intosaid metering chamber, a second passage connecting said first passage tosaid metering chamber, a valve member having a free end and one endconnected to said plunger and reciprocally received in said orifice tocontrol fluid flow through said orifice and into said metering chamber,a first guide sleeve in said valve body for supporting the free end ofsaid valve member and permitting movement of said free end axially ofsaid guide sleeve, an output chamber in said body in communication withsaid first passage, a second guide sleeve, a spacer located between andseparating said first and second guide sleeves, said spacer having aninterior which receives the free end of said valve member, a free pistonreciprocal in said second guide sleeve and having one end exposed tosaid output chamber and the other end engaging the free end of saidvalve member.

1. A hydraulic valve comprising a valve body having an axial bore, aplunger reciprocally received in said bore, said body having an inletport and an outlet port, a first passage connecting said inlet port tosaid outlet port, means defining a metering chamber in said body, a ventpassage communicating with said metering chamber, means defining ametering orifice in said metering chamber, a second passage affordingcommunication between said first passage and said metering chamber, ametering valve member having a portion with a variable cross sectionmovable in said orifice, means for supporting and guiding one end ofsaid metering valve member and means connecting said metering valvemember to said plunger to afford movement of said valve member in saidorifice in response to movement of said plunger to vary output pressureat said outlet port.
 2. A hydraulic valve in accordance with claim 1wherein said means for supporting and guiding one end of said meterIngvalve member comprises a guide sleeve having an axial aperture whichfreely receives said one end of said metering valve member and interfitswith said one end to provide a fluid seal between said valve member andsaid sleeve.
 3. A hydraulic valve in accordance with claim 1 whereinsaid metering valve member is cylindrical and said variable crosssection of said metering valve member is in the form of axially taperedflat.
 4. A hydraulic valve in accordance with claim 1 wherein saidmetering valve member has a frustoconical portion intermediate twocylindrical portions.
 5. A hydraulic valve in accordance with claim 1including a free piston, means for supporting said free piston in saidvalve body for axial movement, said free piston having one end exposedto said first passage adjacent said outlet port and another end engagingsaid metering valve member to transmit a counter force from said pistonto said plunger in a direction opposite to the input force on saidplunger.
 6. A hydraulic valve in accordance with claim 5 wherein saidmeans for supporting said free piston comprises a guide sleeve having anaxial aperture with said piston freely slidable therein and interfittingin said aperture to provide a fluid seal, a spacer in said valve bodyand a spring biasing said sleeve against said spacer.
 7. A hydraulicvalve in accordance with claim 6 wherein said valve body has an outputchamber communicating with said first passage, an adapter threadablyreceived in said valve body and having an aperture defining said valveoutlet, said outlet communicating with said output chamber, acounterbore in said adapter providing a stop for said piston and whereinsaid spring is arranged around the path of travel of said piston topermit movement of said piston within the interior of said spring.
 8. Ahydraulic valve comprising a valve body having a bore, a valve inlet anda valve outlet, a first passage connecting said inlet and outlet, aplunger reciprocally received in said bore for controlling flow throughsaid first passage from said inlet to said outlet, a metering chamber, asecond passage communicating with said first passage and said meteringchamber, a metering valve assembly including means defining an orificeand a metering valve member located axially of said plunger and movablewith said plunger, said valve member having a portion with a variablecross section receivable in said orifice, a vent passage communicatingwith said metering chamber, a free piston located in tandem with saidmetering valve member and having one end engaging said metering valvemember and another end exposed to said first passage downstream fromsaid second passage so that fluid pressure on said exposed end causes acounterforce on said piston which is transmitted to said plunger by saidmetering valve member and which opposes the input force on the plunger.9. A hydraulic valve comprising a valve body having an axial bore, aplunger reciprocally received in said bore, said valve body having aninlet port and an outlet port, a first passage connecting said inletport and said outlet port, a metering chamber in said body, a ventpassage communicating with said metering chamber and adapted tocommunicate with a reservoir, an orifice for permitting fluid flow intosaid metering chamber, a second passage connecting said first passage tosaid metering chamber, a valve member having a free end and one endconnected to said plunger and reciprocally received in said orifice tocontrol fluid flow through said orifice and into said metering chamber,a first guide sleeve in said valve body for supporting the free end ofsaid valve member and permitting movement of said free end axially ofsaid guide sleeve, an output chamber in said body in communication withsaid first passage, a second guide sleeve, a spacer located between andseparating said first and second guide sleeves, said spacer having aninterior which receives the free end of said valve member, a free pistonReciprocal in said second guide sleeve and having one end exposed tosaid output chamber and the other end engaging the free end of saidvalve member.